1 files changed, 47 insertions, 0 deletions
diff --git a/compiler/rustc_hir/src/weak_lang_items.rs b/compiler/rustc_hir/src/weak_lang_items.rs
new file mode 100644
index 000000000..b6a85c047
--- /dev/null
+++ b/compiler/rustc_hir/src/weak_lang_items.rs
@@ -0,0 +1,47 @@
+//! Validity checking for weak lang items
+
+use crate::def_id::DefId;
+use crate::{lang_items, LangItem, LanguageItems};
+
+use rustc_ast as ast;
+use rustc_data_structures::fx::FxIndexMap;
+use rustc_span::symbol::{sym, Symbol};
+
+use std::sync::LazyLock;
+
+macro_rules! weak_lang_items {
+    ($($name:ident, $item:ident, $sym:ident;)*) => (
+
+pub static WEAK_ITEMS_REFS: LazyLock<FxIndexMap<Symbol, LangItem>> = LazyLock::new(|| {
+    let mut map = FxIndexMap::default();
+    $(map.insert(sym::$name, LangItem::$item);)*
+    map
+});
+
+pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol>
+{
+    lang_items::extract(attrs).and_then(|(name, _)| {
+        $(if name == sym::$name {
+            Some(sym::$sym)
+        } else)* {
+            None
+        }
+    })
+}
+
+impl LanguageItems {
+    pub fn is_weak_lang_item(&self, item_def_id: DefId) -> bool {
+        let did = Some(item_def_id);
+
+        $(self.$name() == did)||*
+    }
+}
+
+) }
+
+weak_lang_items! {
+    panic_impl,         PanicImpl,          rust_begin_unwind;
+    eh_personality,     EhPersonality,      rust_eh_personality;
+    eh_catch_typeinfo,  EhCatchTypeinfo,    rust_eh_catch_typeinfo;
+    oom,                Oom,                rust_oom;
+}